Thread (7 messages) 7 messages, 3 authors, 2021-08-07

Re: [PATCH 1/2] mm/PAGE_IDLE_FLAG: Set PAGE_EXTENSION for none-64BIT

From: Randy Dunlap <hidden>
Date: 2021-08-07 02:02:03
Also in: linux-fsdevel, linux-mm, lkml, mm-commits

On 8/6/21 2:51 AM, SeongJae Park wrote:
From: SeongJae Park <redacted>

Commit 128fd80c4c07 ("mm/idle_page_tracking: Make PG_idle reusable") of
linux-mm[1] allows PAGE_IDLE_FLAG to be set without PAGE_EXTENSION
while 64BIT is not set.  This makes 'enum page_ext_flags' undefined, so
build fails as below for the config (!64BIT, !PAGE_EXTENSION, and
IDLE_PAGE_FLAG).

     $ make ARCH=i386 allnoconfig
     $ echo 'CONFIG_PAGE_IDLE_FLAG=y' >> .config
     $ make olddefconfig
     $ make ARCH=i386
     [...]
     ../include/linux/page_idle.h: In function ‘folio_test_young’:
     ../include/linux/page_idle.h:25:18: error: ‘PAGE_EXT_YOUNG’ undeclared (first use in this function); did you mean ‘PAGEOUTRUN’?
        return test_bit(PAGE_EXT_YOUNG, &page_ext->flags);
     [...]

This commit fixes this issue by making PAGE_EXTENSION to be set when
64BIT is not set and PAGE_IDLE_FLAG is set.

[1] https://github.com/hnaz/linux-mm/commit/128fd80c4c07

Fixes: 128fd80c4c07 ("mm/idle_page_tracking: Make PG_idle reusable")
Reported-by: Randy Dunlap <redacted>
Signed-off-by: SeongJae Park <redacted>
Acked-by: Randy Dunlap <redacted> # build-tested

Thanks.
quoted hunk ↗ jump to hunk
---
  mm/Kconfig | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/Kconfig b/mm/Kconfig
index d0b85dc12429..50ca602edeb6 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -741,6 +741,7 @@ config DEFERRED_STRUCT_PAGE_INIT
  
  config PAGE_IDLE_FLAG
  	bool "Add PG_idle and PG_young flags"
+	select PAGE_EXTENSION if !64BIT
  	help
  	  This feature adds PG_idle and PG_young flags in 'struct page'.  PTE
  	  Accessed bit writers can set the state of the bit in the flags to let
@@ -749,7 +750,6 @@ config PAGE_IDLE_FLAG
  config IDLE_PAGE_TRACKING
  	bool "Enable idle page tracking"
  	depends on SYSFS && MMU && BROKEN
-	select PAGE_EXTENSION if !64BIT
  	select PAGE_IDLE_FLAG
  	help
  	  This feature allows to estimate the amount of user pages that have

-- 
~Randy
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